Notifications API support for images with multiple scale factors.

chrome/renderer/resources/extensions/notifications_test_util.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // NotificationsTestUtil contains stubs for the global classes and
 // variables used by notifications_custom_bindings.js that are not
 // available with gtestjs tests.
 var require = function(library) {
   return {
     binding: {
@@ skipping 22 matching lines @@
           image: { width: 0, height: 0 },
           buttonIcon: { width: 0, height: 0}
         };
       }
     }
   }[library];
 }
 
 var exports = {};
 
-var $Array = {
-  push: function (ary, val) {
-    ary.push(val);
-  }
-};
+function makeStaticFunction(obj, methodName) {
+  return function() {
+    var self = arguments[0];
+    var args = Array.prototype.slice.call(arguments, 1);
+    return obj.prototype[methodName].apply(self, args);
+  };
+}
 
-var $Function = {
-  bind: function (fn, context) {
-    return fn.bind(context);
-  }
-};
+var $Array = { self: Array };
+["push", "concat", "splice", "forEach"].forEach(function (name) {
+  $Array[name] = makeStaticFunction(Array, name);
+});
+
+var $Function = { self: Function };
+["bind"].forEach(function(name) {
+  $Function[name] = makeStaticFunction(Function, name);
+});
+
+var $String = { self: String };